The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
Free tracker included with every download this week
Mounjaro Weight Loss Tracker: NHS & UK Information
Tracking your weight loss progress with Mounjaro is an important part of your treatment journey. In the UK, Mounjaro (tirzepatide) is a prescription-only weekly weight loss injection approved by the MHRA and recommended by NICE for eligible adults. This guide explains how to monitor your progress, what to expect during dose titration, and how the NHS and private prescribing routes work. Using a weight loss tracker alongside your Mounjaro treatment helps you identify patterns, stay motivated, and provide your prescriber with accurate data during follow-up appointments.
10,000+ calculations today · NHS-aligned thresholds · 100% free
Calculate Your BMI Instantly
Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
NHS Eligibility and Mounjaro Prescribing in the UK
In the UK, Mounjaro is available through two routes: NHS specialist weight management services (tier 3) and private online prescribing. NHS eligibility requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, hypertension, dyslipidaemia, or cardiovascular disease. Lower thresholds apply for adults of South Asian, Chinese, Black African, or Black Caribbean heritage (BMI 27.5+). However, NHS access is limited — tier 3 services are regional, often have waiting lists of several months or years, and prescribing varies by ICB. NICE has approved tirzepatide for NHS use within specialist weight management services, but availability depends on your local area. Your GP can refer you to your regional tier 3 service, but many patients access Mounjaro through private prescribing following an online clinical assessment instead. Using our free BMI calculator above helps determine whether you meet eligibility criteria and what your starting point is.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
Tracking Progress: Dose Titration and Weekly Monitoring
Mounjaro uses a structured dose titration schedule — starting at 2.5 mg and increasing every 4 weeks up to 15 mg, depending on your response and tolerability. Weekly weight loss tracking during dose titration shows how your body responds to each dose level. Most people see modest initial changes in appetite and fullness within the first 1–2 weeks, followed by measurable weight loss beginning around week 3–4. Keep a simple log of your weight each week (same time, same day) alongside notes on appetite, energy, side effects, and exercise. This data becomes invaluable at your prescriber follow-up appointments — typically every 4 weeks during dose escalation. Try our GLP-1 weight loss calculator to project potential outcomes at different dose levels, and use our progress tracker to log weekly weight and monitor your individual response pattern. Remember that results vary significantly; clinical trials showed average weight loss of 15–21% body weight, but your individual trajectory may differ.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
How often should I weigh myself when taking Mounjaro?
Weekly weighing (same day and time) is typical for tracking Mounjaro progress. Daily weighing can show normal fluctuations that may be discouraging. Use our free progress tracker to log weekly results and identify patterns over 4-week dose cycles. Share this data with your prescriber at follow-up appointments.
What weight loss should I expect in the first month of Mounjaro?
In the first 4 weeks (starting dose 2.5 mg), most people notice appetite reduction but minimal weight loss — typically 0–2 kg. Measurable weight loss usually begins in weeks 3–4 onwards as the dose takes effect. Individual results vary significantly based on diet, activity, and personal metabolism.
Is Mounjaro available on the NHS in my area?
NHS Mounjaro access is through tier 3 specialist weight management services, which vary significantly by region. Ask your GP to refer you to your local service, but waiting times can be several months. Many UK patients access Mounjaro privately through online prescribing instead, following a clinical assessment.
Can I track weight loss if I'm switching from another weight loss injection?
Yes — if switching to Mounjaro from Wegovy or Saxenda, you may see different weight loss patterns because Mounjaro is a dual GIP and GLP-1 agonist. Start fresh tracking at the new dose level and monitor your individual response. Your prescriber will advise on the transition timing.
What should I record in a weight loss tracker alongside my weight?
Log weekly weight, appetite levels, energy, side effects (nausea, constipation, etc.), physical activity, and diet notes. This information helps your prescriber assess tolerability and decide whether to increase your dose or maintain your current level during your 4-week review.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.